Method and Device for Dispensing Sealing Compound, and Housing for an Electric Machine

ABSTRACT

In a method for connecting a housing cover to a cup-shaped housing structure for an electric machine, and a cup-shaped housing structure produced by means of the method, the cup-shaped housing structure has an opening and has an opening edge surrounding the opening. The housing cover is of cup-shaped form, wherein a collar of uninterrupted encircling form is integrally formed on a cup-shaped structure wall in the region of an opening edge, which collar points radially outward. In a first method step, the housing cover is at least partially inserted into the housing opening such that a channel is formed by mutually opposite regions of the housing cover wall and of the cup-shaped housing structure wall. In a further step, the channel is at least partially or completely filled with a sealing compound, which is in particular of elastic form, or an adhesive.

DISCLOSURE OF THE INVENTION

The invention relates to a method for connecting a housing cover to ahousing cup for an electric machine.

The housing cup has an opening and an opening edge surrounding theopening. The housing cover is of cup-shaped form, wherein a collar of inparticular uninterrupted encircling form is integrally formed on a cupwall in the region of an opening edge, which collar points radiallyoutward.

In a first method step, the housing cover is at least partly insertedinto the housing opening, so that a channel is formed by mutuallyopposite regions of the housing cover wall and the housing cup wall. Ina further step, the channel is at least partly or completely filled witha sealing compound which is in particular of elastic form or anadhesive. Advantageously, the housing cup and the housing cover can thusboth be bonded and also sealed off relative to each other in one methodstep, namely the filling of the channel with the sealing compound.

In a preferred embodiment, to fill the channel with the sealingcompound, a dispensing device is inserted into the channel, which causesthe sealing compound to flow into the channel. Advantageously, thechannel can thus be filled cleanly.

In a preferred embodiment, the dispensing device is a dispensing pipe,which is guided circumferentially around the housing cover in thechannel and puts the sealing compound into the channel as it is guided.The sealing compound can emerge here from an opening at one pipe end.

Thus, the sealing compound can advantageously be put into the channelmechanically and automatically.

In a preferred embodiment, a channel width and a depth extent of thechannel as far as the collar is detected, and a volume of the sealingcompound put in is changed along the channel circumference as a functionof location in such a way that a filling level of the sealing compoundas far as the housing cup edge is constant along the circumference.Advantageously, a non-central contact of the housing cover on thehousing cup, which effects a radially circumferentially increasing ordecreasing gap width of the channel, thus cannot lead to the sealingcompound overflowing out of the channel, and thus to the housing cupbeing contaminated. Advantageously, the channel can thus be filled flushas far as the housing cup edge.

In a preferred embodiment, the channel depth is detected in particularinterferometrically by means of electromagnetic radiation.Advantageously, the channel depth can thus be detected reliably.

In a preferred embodiment, the channel width is determined by means ofan image capture device, and for this purpose an image dataset isproduced, which represents the channel in a top view. Advantageously,the channel width can thus be detected reliably and automatically.

In a preferred embodiment, the sealing compound is put in as far as theedge of the housing cup and ends flush with the edge. Advantageously, anoverlap width along the longitudinal extent of the housing cup, on whichthe housing wall of the housing cup and the wall of the housing coveroverlap each other, can thus be used completely for bonding the housingcover and the housing cup adhesively to each other.

In a preferred embodiment, the sealing compound is thixotropic, whereinthe sealing compound has a greater viscosity following the dispensing,in particular having been put into the channel, than as it is put intothe channel. Advantageously, the sealing compound thus cannot flow intothe housing interior through a gap formed between the collar and thehousing cup wall. During the filling process, the sealing compound inthe region of the dispensing pipe can still flow over an in particularpredetermined flow section and thus fill the channel, wherein theflowing process of the sealing compound is then stopped by theincreasing viscosity of the sealing agent.

Preferably, the sealing compound is designed, activated by means ofultraviolet radiation, to be cured by polyaddition. In a method step,the sealing compound, after being put into the channel, can be cured forthis purpose by means of ultraviolet radiation emitted onto the sealingcompound by an emitter for ultraviolet radiation. Preferably, thesealing compound is an elastomer, in particular a silicone elastomercross-linked by means of ultraviolet radiation by means of polyaddition.The housing can thus advantageously be sealed so as to be media-tightwith respect to media such as water or oil.

The invention also relates to a housing for an electric machine, inparticular produced by the method of the above-described type. Thehousing has a housing cup with an opening, and a housing cover, which isdesigned to close the opening of the housing cup.

The housing cover is preferably of cup-shaped form. The housing cup hasa cup wall, wherein a collar of uninterrupted encircling form isintegrally formed on the cup wall in the region of an opening edge. Thecollar points radially outward, so that—in particular when the housingcup is closed—the collar forms a channel bottom of a channel. Thechannel is formed by mutually opposite regions of the cup wall of thehousing cover and of the housing cup. The channel is filled by means ofa sealing compound which is in particular of elastic form or anadhesive. Advantageously, the housing can thus be provided with littleoutlay and sealed off simply. Also advantageously, the housing cover isthus firmly bonded to the housing cup by means of the sealing compound.

The invention also relates to a device for dispensing sealing compoundor an adhesive into a channel running around a housing cover. The devicehas a detection device, which is designed to detect a channel depth anda channel width along the radial channel circumference, and is designedto produce a depth dataset representing the channel depth and a widthdataset representing the channel width.

The device preferably has a dispensing device for putting sealingcompound into the channel and is designed to produce a sealing compoundvolume dataset, depending on the depth dataset and depending on thewidth dataset, which sealing compound volume dataset represents asealing material volume to be dispensed by a dispensing device into thechannel along the radial circumference and to fill the channel withsealing compound depending on the sealing compound volume dataset insuch a way that the sealing compound does not overrun the housing cupedge. Advantageously, the sealing compound thus cannot overflow atnarrow points of the channel along the channel circumference.

The invention will now be described below by using figures and furtherexemplary embodiments. Further advantageous design variants emerge froma combination of the features described in the dependent claims and inthe figures.

FIG. 1 shows an exemplary embodiment of a system for joining a housingcover to a housing cup, wherein a channel formed between the housingcover and the housing cup is surveyed by means of image capture and bymeans of an interferometer and, depending on the volume of the channeldetermined from the measurement, is suitably filled with sealingcompound.

FIG. 2 shows the housing cover shown in FIG. 1 and the channel in a topview.

FIG. 1 shows an exemplary embodiment of a system 1 for joining a housingcover 11 to a housing cup 10, wherein the housing cup 10 and the housingcover 11 are a constituent part of a housing for an electric machine.

The housing cup 10 encloses a cavity 17, in which components of theelectric machine are accommodated. In this exemplary embodiment, thehousing cover 11 is of cup-shaped form and encloses a cavity 18. Acollar 12 of encircling form adjoining a housing cover wall 41 of thehousing cover forms a housing cover edge.

The system 1 comprises a device 2, which is designed to fill a channel13 formed between the housing cover 11 and the housing cup 10 with asealing compound 28. The collar 12 integrally formed on the wall 41 ofthe housing cover here forms a bottom of the channel 13 when the housingcup 10 is closed.

To this end, the device 2 has an image capture device 3, wherein theimage capture device 3 has a detector 4 for detecting electromagneticimage radiation 29. The detector 4 is designed to produce an imagedataset, depending on the image radiation 29 received, which datasetrepresents an object, in particular the housing cup 10 and the housingcover 11, in a top view. To this end, the detector 4 has a multiplicityof matrix elements, of which one matrix element 5 is designated by wayof example. The matrix elements are each designed to generate a matrixelement signal which represents a brightness value and/or a color valueof the image radiation 29 received.

The detection device 3 is designed to produce the image dataset as afunction of the matrix element signals and to output the same on anoutput. The device 2 also has a processing unit 6, in particular amicroprocessor or a microcontroller. The processing unit 6 is designedto determine a width dimension 15 of the channel 3 along a channelcircumference around the housing cover 11, depending on the imagedataset 9 received on the input, and to produce a width dataset which—inparticular as a function of location—represents a channel width of thechannel along the channel circumference.

The processing unit 6 is connected to a memory 8 via a bidirectionalconnection 34 and is designed to produce a width dataset 35 whichrepresents the determined channel width along the channel circumference,and to store the same in the memory 8 via the connection 34.

The device 2 also has a positioning device 25 and a filling device 26which is connected to the positioning device 25 and which is designed toput the aforementioned sealing compound 28 into the channel along thechannel circumference. The positioning device 25 is designed to move thefilling device in at least two translational degrees of freedom, inparticular to move to a position in a plane as a function of anactuating signal. The positioning device 25 is connected to theprocessing unit 6 via a connecting line 33 for this purpose, and canthus receive the actuating signal generated by the processing unit 6.

In this exemplary embodiment, the positioning device 25 is furtherdesigned to move the filling device 26, in particular a dispensing pipeconnected to the filling device 26,—in particular as a function of theactuating signal—transversely with respect to the translational degreesof freedom. Thus, the positioning device can move the dispensing pipeinto the channel 13, so that the sealing compound 28 can be put in thereby the dispensing device 26.

In this exemplary embodiment, the device 2 also has a depth detectiondevice 7 for detecting a channel depth 14 of the channel 13. The depthdetection device 7 in this exemplary embodiment is formed by a laserinterferometer, which is designed to transmit electromagnetic laserradiation 30 in the direction of the channel 13, which radiation is tobe reflected at the channel bottom, in this exemplary embodiment fromthe circumferentially formed collar 12 of the housing cover 11, and isreflected back to the depth detection device 7 as reflected laserradiation 30′. The depth detection device 7 is designed to generate adepth signal as a function of the received laser radiation 30′, whichsignal represents a distance of the depth detection device 7 from thechannel bottom, in particular the collar 12, and to transmit this depthsignal to the processing unit 6 via a connecting line 31.

The processing unit 6 is designed to determine the channel depth 14 ofthe channel 13 as a function of the depth signal received by the depthdetection device 7—for example as a function of a previously storedoffset—and to produce a depth dataset 36 which represents a channeldepth 14 of the channels 13 along the radial circumference. Theprocessing unit 6 can store the depth dataset 36 in the memory 8.

The processing unit 6 in this exemplary embodiment is designed todetermine a sealing material volume to be dispensed by the dispensingdevice 26 into the channel 13 along the radial circumference dependingon the width dataset and on the depth dataset, and to produce acorresponding sealing compound volume dataset. The processing unit 6 isalso designed to store the sealing compound volume dataset 37 in thememory 8.

The housing for the electric machine, comprising the housing cup 10 andthe housing cover 11, can then be joined together as follows:

The housing cover 11 can be inserted into a housing cup opening of thehousing cup 10 until the radially projecting collar 12 is spaced apartfrom a housing cup edge 16 by the magnitude of the channel depth 14.

In this exemplary embodiment, the housing cup 10 comprises a coolingplate 19, to which at least one electric component, in particular acontrol unit 20, is thermally conductively connected. The housing cover11, in particular the collar 12 of encircling form, then comes to lie onthe cooling plate 19 after the housing cover 11 has been inserted intothe housing cup 10. Between a wall 41 of the housing cover 11 and a wallof the housing cup 10, a channel having a channel width 15 is thenformed, insofar as a diameter of the housing cover 11 is smaller than anopening of the housing cup 10.

Then—as previously described—the device 2 can produce the image dataset9 and, as a function of the image dataset 9 and also as a function ofthe laser radiation 30′ reflected from the channel bottom, in particularthe collar 12, can produce the sealing compound volume dataset 37 andstore the same in the memory 8.

In a further method step, the filling of the channel 13 with the sealingcompound 28 can then be carried out. To this end, the processing unit 6can determine the quantity, in particular volume and/or mass, of sealingcompound to be dispensed for each location of the channel along theradial circumference, as a function of the sealing compound volumedataset 37 read from the memory 8, and transmit an actuating signal tothe positioning device 25 via the connecting line 33 in order to movethe dispensing device 26 to the appropriate location of the channel 13.

The processing unit 6 can thus control the positioning device 25 in sucha way that the dispensing device 26 moves the dispensing pipe 27 in thechannel 13 along the radial circumference in the channel along a closedcurve and, in the process, for each channel location in the channelalong the radial circumference, determine a quantity of sealing compoundfor each location of the channel along the material circumference—as afunction of the sealing compound volume dataset 37 determined. Thedispensing device 26 can then put the corresponding quantity of sealingcompound into the channel for each channel location along the radialcircumference as it is guided along in the channel, in particular byadapting the volume flow of the sealing compound.

The dispensing device 26 is designed to change a volume of the sealingcompound to be dispensed per time interval. Thus, the channel can befilled continuously along the channel circumference by the dispensingdevice 26, wherein—in a manner dependent on a channel width which canchange along the radial circumference—a filling level of the sealingcompound in the channel which is constant along the radial circumferencecan be produced by the dispensing device by means of a quantity of thedischarged sealing compound that changes along the channelcircumference. The channel 13 can be filled with sealing compound by wayof a single pass or multiple passes around the channel circumference.

In a further step, the sealing compound 28, in particular a siliconeelastomer cross-linked by irradiation by means of ultraviolet radiation,can be cured by means of ultraviolet radiation emitted onto the sealingcompound—from a transmitter for ultraviolet radiation not illustrated inFIG. 1.

The housing cup 10 and the housing cover 11 can be a constituent part ofan electric machine. In this regard, FIG. 1 shows electric components ofan electric machine, which are accommodated in the housing cup 10.

In this regard, the electric machine comprises the aforementionedcooling plate 19, the control unit 20, a bearing shield 21, a rotor 23,which is rotatably mounted in the bearing shield 21, and an output powerstage 22, which is thermally conductively connected to the bearingshield 21. The machine also comprises a stator comprising stator coils24.

FIG. 2 shows an exemplary embodiment of an image dataset 9 which—asalready shown in FIG. 1—can have been produced by the detection device3.

The image dataset 9 represents the housing cover 11 and the housing cup10, in particular the housing cup edge 16, in a top view. In thisexemplary embodiment, the housing cover 11 has not been insertedcentrally, and thus has been inserted eccentrically, into an opening ofthe housing cup 10, such that a channel width 15 of the channel 13varies along a radial channel circumference 38. The channel width 15 ofthe channel 13 is thus, for example, formed to be narrower at a channellocation 39 than at a channel location 40 that is opposite thereto. Thedevice 2 illustrated in FIG. 1 can then fill the channel 13 uniformlywith sealing compound 28 along the channel circumference 38, with aconstant filling level along the channel circumference 38.

1. A method for connecting a housing cover to a housing cup for anelectric machine, the housing cup defining an opening and having anopening edge surrounding the opening, the housing cover having a cupshape, and a collar of uninterrupted encircling form is integrallyformed on a cup wall of the housing cover in a region of the openingedge, the collar projecting radially outwardly, the method comprising:at least partially inserting the housing cover into the housing openingsuch that a channel is formed by mutually opposite regions of a housingcover wall and a housing cup wall; and at least partially filling thechannel with a sealing compound.
 2. The method as claimed in claim 1,wherein the at least partial filling of the channel with the sealingcompound comprises inserting a dispensing device into the channel, whichcauses the sealing compound to flow into the channel.
 3. The method asclaimed in claim 2, wherein the dispensing device includes a dispensingpipe, and the at least partial filling of the channel further comprises:circumferentially guiding the dispensing pipe around the housing coverin the channel; and dispensing the sealing compound into the channel asit the dispensing pipe is guided around the housing cover.
 4. The methodas claimed in claim 1, further comprising: detecting a channel width anda depth extent of the channel as far as the collar; and the at leastpartially filling of the channel includes changing a volume of thesealing compound filled into the channel along the channel circumferenceas a function of location in such a way that a filling level of thesealing compound as far as the housing cup edge is constant along acircumference of the channel.
 5. The method as claimed in claim 4,wherein the detecting of the channel depth comprises detecting thechannel depth interferometrically using electromagnetic radiation. 6.The method as claimed in claim 4, wherein the detecting of the channelwidth includes using an image capture device to produce an image datasetthat represents the channel in a top view.
 7. The method as claimed inclaim 1, wherein the at least partial filling of the channel with thesealing compound includes filling the channel as far as an edge of thehousing cup such that the sealing compound ends flush with the edge. 8.The method as claimed in claim 1, wherein the sealing compound isthixotropic and has a greater viscosity following the the at leastpartial filling of the channel than during the at least partial fillingof the channel.
 9. A housing for an electric machine, comprising: ahousing cup defining an opening; and a housing cover configured to closethe opening of the housing cup, the housing cover having a cup share,wherein a collar of uninterrupted encircling form integrally formed on acup wall of the housing cover in a region of an opening edge, the collarprojecting radially outwardly such that, when the housing in closed, thecollar forms a channel bottom of a channel that is defined by mutuallyopposite regions of the cup wall of the housing cover and of a wall ofthe housing cup, and wherein the channel is filled by a sealingcompound.
 10. A device for dispensing sealing compound into a channelthat extends around a housing cover, the device comprising: at least onedetection device configured to detect a channel depth of the channel anda channel width of the channel along a radial channel circumference; adispensing device configured to dispense the sealing compound into thechannel, wherein the device is configured to: using the at least onedetection device, produce a depth dataset representing the channel depthand a width dataset representing the channel width; produce the asealing compound volume dataset based on the depth dataset and the widthdataset, the sealing compound volume dataset representing a sealingmaterial volume to be dispensed by the dispensing device into thechannel along the radial channel circumference; and operate thedispensing device to fill the channel with sealing compound depending onthe sealing compound volume dataset in such a way that the sealingcompound does not overrun an edge of the housing cup.
 11. The method asclaimed in claim 1, wherein the sealing compound is an elastic sealingcompound.
 12. The housing as claimed in claim 9, wherein the sealingcompound is an elastic sealing compound.